U.S. patent number 5,485,293 [Application Number 08/130,599] was granted by the patent office on 1996-01-16 for liquid crystal display including color triads with split pixels.
This patent grant is currently assigned to Honeywell Inc.. Invention is credited to Ronald C. Robinder.
United States Patent |
5,485,293 |
Robinder |
January 16, 1996 |
Liquid crystal display including color triads with split pixels
Abstract
An active liquid crystal multi-colored display panel structure
comprised of triangular triads of colored display pixels which are
rotated 90.degree.. The display comprises a plurality of colored
pixel electrodes arranged in rows and columns to form a matrix,
wherein a row control line is provided every 1.5 rows of
electrodes, and wherein three column control lines are provided for
each two columns of electrodes. Thus, a matrix of 720.times.720
pixel electrodes requires 480 row control lines and 1080 column
signal lines. The active liquid crystal display structure can be
directly driven by a video source such that 480 active lines of
video signal can be mapped directly onto the 720 rows of pixel
elements. A switching circuit is provided for controlling the
arrangement of R, G and B pixel signals to the column source lines.
The triads of pixel elements provided are rotated 90.degree. to
maintain high resolution while allowing a standard video signal to
be directly mapped onto the display without additional electronics
such as a ping-pong memory.
Inventors: |
Robinder; Ronald C.
(Albuquerque, NM) |
Assignee: |
Honeywell Inc. (Minneapolis,
MN)
|
Family
ID: |
22445442 |
Appl.
No.: |
08/130,599 |
Filed: |
September 29, 1993 |
Current U.S.
Class: |
345/88; 345/92;
349/144 |
Current CPC
Class: |
G09G
3/3607 (20130101); G02F 1/1368 (20130101); G09G
2300/0452 (20130101); G02F 1/133514 (20130101); G02F
1/134345 (20210101); G02F 2201/52 (20130101); G09G
3/3648 (20130101) |
Current International
Class: |
G02F
1/1368 (20060101); G09G 3/36 (20060101); G02F
1/13 (20060101); G02F 1/1343 (20060101); G02F
1/1335 (20060101); G02F 001/1335 (); G02F
001/1343 () |
Field of
Search: |
;359/59,68
;345/88,92 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sikes; William L.
Assistant Examiner: Trice; Ron
Attorney, Agent or Firm: Johnson; Kenneth J. Nikolai; Thomas
J.
Claims
The embodiments of the invention in which an exclusive property or
right is claimed are defined as follows:
1. A liquid crystal multi-color display panel structure,
comprising:
(a) a substantially transparent substrate;
(b) a plurality of color display pixel electrodes disposed on said
substrate in a matrix array having columns extending in a first
direction and rows extending in a second direction transverse to
said first direction, said color display pixel electrodes
consisting of those of a first type for displaying in a first
preselected color, those of a second type for displaying in second
preselected color different from said first preselected color, and
those of a third type for displaying in a third preselected color
different from said first and second preselected colors, the color
display pixel electrodes of each of said columns being
approximately a half pitch distance offset from the color display
pixel electrodes of the adjacent column, wherein one of said pixel
electrode of each said first, second and third preselected colors
together form a generally triangular triad having one side
extending in a vertical direction;
(c) a plurality of signal lines disposed between the columns of
said electrodes forming the matrix array and extending in the first
direction, wherein a single one of said plurality of signal lines
is alternately disposed between adjacent ones of said columns, and
wherein two of said plurality of signal lines are alternately
disposed between adjacent ones of said columns such that there are
three total of said plurality of signal lines for every two of said
columns;
(d) a plurality of scanning lines, one scanning line being disposed
every one and one-half rows of said electrodes forming said matrix
array and extending in the second direction between two said
electrodes of said first and second types in alternating ones of
said columns and bifurcates one said electrode of said third type
into a first and second half in alternating ones of said
columns;
(e) a plurality of switching transistors, each said transistor
having a first terminal connected to one of said color display
pixel electrodes, a second terminal connected to one of said signal
lines, and a third terminal connected to one of said scanning lines
to control conductivity between the respective first and second
terminals;
(f) row drive means connected to said scanning lines for driving
each said plurality of scanning lines in synchronism with the
horizontal scanning cycle of a video signal;
(g) column drive means having an input, and an output connected to
said signal lines for supplying a video signal to each of said
signal lines where two of every three of said signal lines are
connected to the third terminals of the switching transistors
associated with the pixel electrodes of two of said color types;
and
(h) control means coupled to the input of said column drive means
for controlling which of said video signals are supplied to said
signal lines.
2. The display panel structure of claim 1 wherein said control
means alternatively supplies the video signal of two of said color
types to two of every three of said signal lines.
3. The display panel structure of claim 1 wherein the first and
second halves of said third type of electrodes are electrically
connected together.
4. The display panel structure of claim 1 wherein one of said
switching transistors is connected to each of said first and second
halves of said third type of electrodes with each transistor
disposed on opposite sides of the adjacent scanning line from the
other.
5. A liquid crystal multi-color display panel structure,
comprising:
(a) a substantially transparent substrate;
(b) a plurality of color display pixel electrodes disposed on said
substrate in a matrix array having columns extending in a first
direction and rows extending in a second direction transverse to
said first direction, said color display pixel electrodes
consisting of those of a first type for displaying in a first
preselected color, those of a second type for displaying in second
preselected color different from said first preselected color, and
those of a third type for displaying in a third preselected color
different from said first and second preselected colors, the color
display pixel electrodes of each of said columns being
approximately a half pitch distance offset from the color display
pixel electrodes of the adjacent column, wherein one of said pixel
electrode of each said first, second and third preselected colors
together form a generally triangular triad having one side
extending in a vertical direction;
(c) a plurality of signal lines disposed between the columns of
said electrodes forming the matrix array and extending in the first
direction, wherein a single one of said plurality of signal lines
is alternately disposed between adjacent ones of said columns, and
wherein two of said plurality of signal lines are alternately
disposed between adjacent ones of said columns such that there are
three total of said plurality of signal lines for every two of said
columns;
(d) a plurality of scanning lines, one scanning line being disposed
every one and one-half rows of said electrodes forming said matrix
array and extending in the second direction between two said
electrodes of said first and second types in alternating ones of
said columns and bifurcates one said electrode of said third type
into a first and second half in alternating ones of said
columns;
(e) a plurality of switching transistors, each said transistor
having a first terminal connected to one of said color display
pixel electrodes, a second terminal connected to one of said signal
lines, and a third terminal connected to one of said scanning lines
to control conductivity between the respective first and second
terminals;
(f) row drive means connected to said scanning lines for driving
each said plurality of scanning lines in synchronism with the
horizontal scanning cycle of a video signal;
(g) column drive means having an input, and an output connected to
said signal lines for supplying a video signal to each of said
signal lines where each said signal line is connected to the third
terminal of the switching transistors associated with the
electrodes of two of said color types; and
(h) control means coupled to the input of said column drive means
for controlling which of said video signals are supplied to said
signal lines.
6. The display panel structure of claim 5 wherein said control
means alternatively supplies the video signal of two of said types
of colors to each of said signal lines.
7. The display panel structure of claim 5 wherein the first and
second halves of said third type of electrodes are electrically
connected together.
8. The display panel structure of claim 5 wherein one of said
switching transistors is connected to each of said first and second
halves of said third type of electrodes with each transistor
disposed on opposite sides of the adjacent scanning line from the
other.
Description
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to an active-matrix liquid crystal
multi-color display panel structure, and more particularly, to a
unique display panel structure comprised of generally triangular
triads of colored display pixels arranged to permit 480 scan lines
of data to be mapped directly onto 720 rows of dots while retaining
a normal scanning sense.
II. Discussion of the Prior Art
Active-matrix liquid crystal multi-colored display panel structures
are typically comprised of a matrix of colored display pixels
arranged in rows and columns and which are controlled by
semiconductor switching devices. The semiconductor switching
devices are typically comprised of thin-film transistors of, for
example, the amorphous-silicon field-effect design. Typically,
multi-colored images are produced on liquid crystal display panels
by providing colored filters in association with pixel electrodes
across a layer of liquid crystal. Construction techniques of liquid
crystal multi-colored display panel structures are well known in
the art, and many control schemes can be implemented to control
each of the colored filters.
The pixel arrangement and control scheme can determine the image
quality, resolution, and the unwanted generated picture artifacts
associated with the particular pixel arrangement and control
scheme. Construction of active-matrix liquid crystal multi-colored
display panel structures and some of the associated artifacts are
discussed in detail in U.S. Pat. No. 4,969,718 to Noguchi, et al.,
which is assigned to NEC Corporation, and in U.S. Pat. No.
4,822,142 to Yasui and which is assigned to Hosiden Electronics
Company, Ltd. Both patents are incorporated herein by
reference.
Present research and development efforts are continuously improving
the picture quality of color images generated on display panels.
Arranging colored pixel elements in triangular arrangements,
commonly referred to as triads, is one known design method of
improving picture quality and resolution. Arranging the colored
pixel elements in triads is generally preferred over other
arrangements such as linear groups or "L" shaped groups.
The present invention is directed to facilitate the mapping of
video data from a video source onto a panel which has an
insufficient number of dots to permit a simple 1:1 mapping of the
incoming data onto the display surface. In particular, the problem
addressed is how to map a 480 active line color video onto a
surface with 720 rows of 720 columns of pixel elements or dots. The
video data is typically transmitted from a signal source, such as a
digital map comprising 480 slit samples, each of which is in an
analog data stream format.
A display panel having a matrix display which can accommodate
directly mapping 480 active lines of color video signals onto a
display surface with 720 rows and 720 columns of pixel elements
display while retaining the normal scanning sense is desirable to
reduce cost and design complexity. A restructured panel comprising
pixel electrodes and interconnects to the dots which permits the
panel to be scanned directly, with no need for auxiliary memory or
components is preferred.
OBJECTS OF THE INVENTION
It is accordingly a principal object of the invention to provide a
liquid crystal multi-colored display panel structure which permits
480 scan lines to be mapped directly onto 720 rows of pixel dots
while retaining the normal scanning sense.
It is a further object of the present invention to provide a liquid
crystal multi-colored display panel structure which is composed of
a plurality of triangular triads of multi-colored display pixel
electrodes to ensure a high quality picture with a high
resolution.
It is still yet a further object of the present invention to
provide a liquid crystal multi-colored display panel structure
which incorporates a practical amount of scanning control lines and
column signal lines, and wherein the colored pixel elements are of
an acceptable size to provide high resolution yet which can be
easily manufactured.
It is still yet another object of the present invention to provide
a liquid crystal multi-colored display panel structure wherein the
plurality of triads of pixel elements are arranged and controlled
such that unpleasant display artifacts are reduced.
SUMMARY OF THE INVENTION
The foregoing features and objects are achieved by providing a
liquid crystal multi-colored display panel structure having triads
of colored display pixel electrodes which are rotated 90.degree.,
wherein a scanning control line is provided every 1.5 rows of
electrodes and wherein three column signal lines are provided for
every two columns of colored display pixel electrodes. This design
results in one of the three colors of display pixel electrodes
being bisected throughout the display. This arrangement allows 480
scan lines to be mapped directly onto 720 rows of pixel electrodes
while retaining the normal scanning sense. No auxiliary memory or
line storing is required, and the display panel structure can be
manufactured using practical techniques.
The liquid crystal multi-colored display panel structure comprises
a substantially transparent substrate having a plurality of colored
display pixel electrodes disposed thereon to form a matrix having
columns in the first direction and rows in a second direction. The
colored display pixel electrodes include three types of colors,
namely the primary colors of red, blue and green. The colored
display pixel electrodes in adjacent columns are offset
approximately one-half distance from one another such that they
form a plurality of generally triangular triads which are rotated
90.degree. from conventional and prior art arrangements. Thus, one
side of each triad extends in the vertical direction. A plurality
of column signal lines are disposed between the pixel columns of
the matrix and extend in a first or vertical direction. A single
signal line is provided between alternate adjacent columns of pixel
electrodes, and a pair of signal lines are alternately disposed
between the other adjacent columns, resulting in three column
signal lines for every two columns of pixel electrodes. Thus, the
resulting arrangement is an alternating pattern of one and two
column signal lines extending between the columns of pixel
electrodes.
The second portion of the control structure includes a plurality of
scanning control lines disposed every one and one-half rows of the
matrix display and which extend in a second or horizontal
direction. These scanning control lines extend between two pixel
electrodes of two different colors of a triad in alternating
columns, such that the scanning line extends across or bifurcates
the third pixel electrode of the triad of a third color in
alternating columns. Thus, each triad of pixel electrodes comprises
one pixel electrode of a first and second color on opposite sides
of the horizontal scanning line, while one bifurcated pixel
electrode of the third color is defined to the left or right of the
first two electrodes, such that the triads are interlaced.
A plurality of switching transistors are provided, one coupled to
each of the first and second color types of pixel electrodes, and
one connected to at least one of the two halves of the third color
type of pixel electrodes. The two halves of the third type of
electrodes can either be electrically connected together such that
they are both controlled by one transistor, or a separate
transistor can be provided for each of the halves. Each transistor
is preferably comprised of a thin-film FET having a first terminal
or drain connected to one of the colored display electrodes, a
second terminal or gate connected to one of the signal lines, and
the third terminal or source connected to one of the column
scanning lines to control conductivity between the respective first
and second terminals. The third terminal of the switching
transistors associated with the colored display electrodes of the
first and second colors of each triad are defined on opposite sides
of the scanning control line. As such, the gate or gates associated
of the colored display electrodes of the third color type of each
triad are disposed on one or the other of opposite sides of the
respective scanning line. If both halves of the electrodes of the
third type are electrically tied together, only one switching
transistor is required for both halves of the pixel electrodes.
Otherwise, a separate transistor can control the respective half of
the pixel electrode of the third color type. It is noted that only
one scanning control line is provided for each triad of pixel
electrodes. Thus, only one gate pulse is required per triad and the
control interface need not be complicated.
In one embodiment of the invention, two of every three of the
column signal lines are connected to the second terminals of the
switching transistors associated with the pixels of two different
color types. This provides, for instance, one column signal line to
be connected to only those pixel electrodes of one color type, such
as green in adjacent columns. The other two signal lines will each
be connected to the other two types of pixel electrodes in adjacent
columns, such as the blue and red pixel electrodes. The column
signal lines will control the pixel electrodes of a triad addressed
by the scanning control line. In operation, as the rows of pixel
electrodes of the display are scanned from top to bottom, when
scanning the odd rows, a column signal line will control one color,
such as red. When scanning the even rows, the same signal line will
control the blue color pixel electrodes. Again, the third of every
three column signal lines control electrodes of only one color,
such as green, regardless of whether an even or odd row of pixels
is being scanned.
In another embodiment of the present invention, each of the column
signal lines is connected to the second terminal of the switching
transistors associated with the electrodes of two different color
types. Thus, when scanning odd rows, each column signal line will
control pixel electrodes of one color of each triad, and when
scanning even rows, the same column signal line will control pixel
electrodes of each triad of the other color. The scanning control
line which is scanned determines which electrode is controlled. The
column signal lines provide a variable voltage to each of the
scanned pixel electrodes to generate a field in the liquid crystal
between the respective pixel electrodes and the common electrode to
control the passage of light therethrough. Light having the
appropriate wavelength selected for the color filter associated
with the particular color display is, thus, passed through the
color filter so that a picture element in any of a total of eight
different colors can be produced by a triad of pixels respectively
assigned to the three primary colors. Thus, a full color picture
can be produced which is composed of picture elements with
steplessly varied color tones.
The display panel structure includes control circuitry for
connecting and coordinating the column signals between a control
signal bus and the signal lines, which is dependent on whether an
odd or even row of pixels is being scanned. A row drive circuit is
connected to the scanning control lines for driving each of the
plurality of scan lines in synchronism with the horizontal scanning
cycle of a video signal, and a column drive circuit is connected to
the column signal lines for supplying a video signal to each of the
signal lines wherein the input of the column drive circuit is
connected to a control circuit which provides the video signals
.
BRIEF DESCRIPTION OF TEE DRAWINGS
FIG. 1 is a sectional view showing, in a simplified form, the
general construction of a prior art liquid crystal display
device;
FIG. 2 is a view showing a relation among display electrodes which
are arranged in triads of three-colored display-element sets,
wherein the triads are rotated 90.degree. and wherein the scanning
control lines for each row of triads extends between two electrodes
of different colors and bifurcates one electrode of a third
color;
FIG. 3 is a view showing the relation among display electrodes,
drive lines including column and scanning lines, and the thin film
transistors which control the corresponding electrodes, wherein a
separate thin film transistor is provided for each half of the
bifurcated electrode, and wherein each of the three signal lines
can control electrodes of two different color types;
FIG. 4 is an alternative embodiment of the preferred invention
modified such that one of every three column signal lines controls
an electrode of only one color type, with the other two column
signal lines controlling pixel electrodes of two different color
types;
FIG. 5 is an yet another alternative embodiment of the present
invention wherein the bifurcated pixel electrode of each triad of
the third color is controlled by a single switching transistor and
each half being electrically connected to the other.
Other objects, features and advantages of the present invention
will become apparent to those skilled in the art upon reading the
following Description of the Preferred Embodiment, the "Claims",
and by referring to the drawings herein in which like numerals
refer to like elements.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a liquid crystal display device
which comprises a pair of transparent substrates 10 and 12 and a
liquid crystal 14 sealed therebetween. A plurality of transparent
square display electrodes are provided on the inner surface of one
of the transparent substrates 10 and 12. A transparent common
electrode 18 is provided on the entire inner surface of the other
substrate 12 opposite electrodes 16. The display electrodes 16 are
arranged in rows and columns and are actively controlled by thin
film transistors attached to them. The thin film transistors are
controlled by row or scanning drive lines and column signal drive
lines. A more detailed description of a typical prior art colored
liquid crystal display device is described in U.S. Pat. No.
4,822,142 which is hereby incorporated by reference.
Referring to FIG. 2, the preferred embodiment of an active-matrix
liquid crystal multi-colored display panel structure is generally
shown at 20. Display 20 is manufactured using well-known
techniques, such as techniques used to create the structure shown
in FIG. 1. However, the preferred embodiment of the present
invention is vastly different from prior art displays in that the
arrangement and interconnection of the display electrodes, the row
scanning and column signal drive lines, and the arrangement of the
thin film transistors is unique compared to prior art arrangements.
In FIG. 2, display electrodes 16 are arranged in rows and columns
to form a display matrix as shown. The pixel electrodes 16 are
comprised of one of three colors, namely, the primary colors of
red, blue or green. The pixel electrodes 16 are arranged in a
pattern producing a plurality of generally triangular interleaved
triads of colored display pixels. Each triad comprises one pixel of
each of the three primary colors. These color groups or triads are
represented by the dotted triangular grouping identified at 22.
Each of the triads 22 form a triangle shape and have an apex shown
at 24. Apex 24 is always centered over a respective row or scanning
control line 26. All triads 22 are oriented and interleaved such
that the apex 24 of the triads 22 are disposed on either the right
side or the left side of the triangle as one observes the display
with the column drive lines extending in the vertical direction as
shown in FIG. 2. Hence, electrodes 16 in adjacent columns are
offset from one another one-half pitch distance, which is half the
height of an electrode 16.
The arrangement of pixel electrodes into triads is well known for
providing a picture of enhanced resolution which is free from image
moires. However, the arrangement of the triads 22 in accordance
with the present invention is unique from the prior art because
each triad 22 is rotated 90.degree. such that one side 28 of each
triad 22 extends in the vertical direction. As shown, one complete
pixel electrode 16 of triad 22 lies on the other side of the
respective scanning control line 26, while the third pixel
electrode 16 of the triad proximate apex 24 is divided or
bifurcated by control line 26 with one-half of the bifurcated pixel
electrode 16 situated on each side of control line 26. Thus, only
one of the three pixel electrodes 16 which form each triad 22 is
divided or intersected by a control scanning line 26. None of the
pixel electrodes 16 is intersected by any of the column signal
control lines 30. As shown in FIG. 2, several column signal control
lines 30 are provided. Specifically, there are three control lines
30 for each triad 22. In other words, there are three control lines
for each two columns of pixel electrodes 16, yielding 50% more
signal control lines 30 than columns of pixel electrodes 16. While
this arrangement necessitates a higher interconnect density in the
horizontal direction and also requires additional gray scale driver
electronics, current and improving technologies for integrated
driver electronics, such as chip-on glass or direct transistor
deposition techniques can provide the necessary higher interconnect
densities at a reasonable cost.
Still referring to FIG. 2, a first triad group T.sub.1, and a
second triad group T.sub.2 are shown and are shaded for
illustration purposes. Triad groups T.sub.1 and T2 are also
consistently shown in FIG. 3 as will be discussed shortly. Triads
22, typified by triad T.sub.1, are all arranged with apex 24 to the
right in odd rows of triads and in even rows, such as triad
T.sub.2, the apex 24 is positioned to the left. This arrangement
allows the triads in adjacent rows to interleave and provide a high
density of pixel electrodes 16 per unit area. High density, of
course, translates into high resolution pictures without
undesirable display artifacts.
One key feature of the present invention is that only one scanning
control line 26 is required per triad 22. Hence, only one gate
pulse needs to be provided, allowing for less complex driving
electronics. A control line 26 is provided only every 1.5 rows of
pixel electrodes 16. This design is advantageous over prior art
displays because the pixel electrodes 16 can be larger in area than
pixel electrodes in displays having a scanning line for every row
of pixel electrodes and manufacture is simplified. Moreover, prior
art displays having a scanning control line for every other row of
pixel electrodes are inferior because the smaller electrodes of the
present invention provide higher image quality and resolution.
Thus, the present invention is unique from the prior art due to the
unique design arrangement of the scanning control lines and the
column signal control lines and the rotated triads to achieve a
display panel capable of high quality images yet which can be
directly driven by the control electronics.
Referring to FIG. 3, the relation of the display electrodes 26 to
the column signal drive lines 30, row or scanning drive lines 26,
thin film transistors 40 and drive/control circuitry 42 is
illustrated. For purposes of illustration and clarification,
consecutive row or scanning control lines 26 have been labeled
L.sub.1, L.sub.2, L.sub.3 . . . from top to bottom, and wherein
column signal control lines 30 are referenced left to right as
C.sub.1, C.sub.2, C.sub.3 . . . Triads T.sub.1 and T.sub.2
correspond to the triads discussed in relation to FIG. 2. Each of
pixel electrodes 16 are controlled by a respective thin film
switching transistor 40, as will be discussed in greater detail
shortly. Circuit 42 provides controls and drives the column control
signals, consisting of pixel information, to the three-color
display element sets forming the pixel array, as will now be
described in detail.
Alternate rows of scanning drive lines 26 are driven in synchronism
with the horizontal sync pulses H.sub.syn by the conventional
arrangement of a row register 44 and a row drive circuit 46. More
specifically, all the odd rows labeled L.sub.1, L.sub.3 . . . are
first successively driven in synchronism with the horizontal sync
pulses, and then the even row drive lines, L.sub.2, L.sub.4 . . .
are driven to complete a picture on the display in an interlaced
manner. A switching circuit 50, forming a subset of circuit 42
connects the input signal lines R, G and B to control signal busses
52, 54 and 56 as shown. When the odd rows of triads are being
scanned by the driving electronics via lines L.sub.1, L.sub.3 . . .
, switching circuit 50 routes the signals R, G and B, labeled as
inputs 51, to color signal busses 52, 54, and 56, respectively.
Thus, signal control line C.sub.1 provides red pixel information to
each of the adjacent red pixel electrodes 16, signal control line
C.sub.2 provides green pixel information to each of the adjacent
green pixel electrodes, and signal control line C.sub.3 provides
blue pixel information to each of the adjacent blue pixel
electrodes 16. Subsequently, when even rows of triads are stroke
scanned, via scanning lines, L.sub.2, L.sub.4 . . . , switching
circuit 50 provides the R, G and B pixel information to color
signal busses 56, 52 and 54, respectively. Thus, in the preferred
embodiment, each signal control line C.sub.1, C.sub.2, C.sub.3 . .
. can provide pixel information of two different colors to adjacent
columns of electrodes 16 as controlled by bus switching circuit
50.
A tertiary counter 60 is provided between terminal 72 providing the
H.sub.syn horizontal sync pulse and switching circuit 50. Counter
60 counts to .sub.240 (half the number of total scan lines) as the
row control electronics completes scanning the 240 odd rows of
control lines 26. Counter 60 provides switching circuit 50 a
control signal on line 61 to initiate the rearrangement of the R, G
and B pixel signals to color signal busses 52, 54 and 56 before the
subsequent scanning of the even rows of control signals 26. Thus,
to generate one complete frame on the display 20, the odd row
control lines 26 labeled L.sub.1, L.sub.3 . . . are scanned first,
and then the even control lines 26, labeled L.sub.2, L.sub.4 . . .
are scanned. Switching circuit 50 rearranges the R, G and B inputs
labeled 51 to color signal busses 52, 54 and 56 only twice every
generated frame on the pixel array 20.
To generate an image on display 20, pixel information is first
loaded from the respective colored signal bus 52, 54 and 56 into
column registers 62. A clock signal, CLK, having three times the
dot frequency of the input colored video signal is supplied as a
shift clock from a clock terminal 68 to a shift register 70. The
horizontal sync pulse H.sub.syn is supplied as data from the
terminal 72 to the first stage of the shift register 70 at the
start of each horizontal scanning cycle period. Colored pixel data
from the individual stages of the column register 62 are fetched
successively in response to the respective output of the shift
stages of the shift register 70. Thus, as the odd or even row drive
lines 26 are successively driven in synchronism with the horizontal
sync pulses H.sub.syn by the conventional arrangement of row
registers 44 and row drive circuit 46, pixel data will be provided
by the respective column register 62 via a column driver 71 to the
respective column control line 30.
Multiple parallel column register 62 can be provided, such that
while a gate pulse is active for one of the row control lines 26,
(such as control line L.sub.1), the pixel data for the electrodes
of the next scan line (such as line L.sub.3), is being sampled and
placed into sample and hold registers of the column registers 62.
Thus, when the pixel data is provided on source lines C.sub.1,
C.sub.2, C.sub.3 . . . , as one row of triads of pixels is being
scanned, data for the next row of triads to be scanned is being
routed to color signal busses 52, 54 and 56 which is to be
subsequently loaded into column registers 62. This arrangement
allows the display electrodes 16 to be directly driven without
auxiliary memory or line storage capabilities.
Still referring to FIG. 3, a thin film switching transistor 40,
comprised of a FET, is provided for each red and green pixel
electrode 16. FET 40 is also provided for each of the two blue
pixel electrodes 16 of each triad 22. It is noted that the
arrangement of electrodes could be interchanged such that it is the
green electrodes or the red electrodes 16 which are divided in
half. Hence, limitation to the exact orientation of colored
electrodes by color is not to be inferred. As each control line 26
is scanned, the respective switching transistors 40, having a gate
terminal connected thereto, are rendered conductive. The source
terminal of each switching transistor 40 is connected to an
adjacent control line 30, and the drain terminal of each switching
transistor 40 is connected to the adjacent respective pixel
electrode 16. Thus, as the respective switching transistor 40 is
rendered conductive by the adjacent control line 26, the pixel
information, or voltage on the respective adjacent column signal
line 30, is provided through the conductive FET to the respective
pixel electrode 16. Thus, pixel information provided on the signal
control lines 30 are presented only to the pixel electrodes 16
adjacent the scanned row control line 26. The pixel information for
the bifurcated blue pixel electrodes 16 is provided to each of the
pixel electrodes, via the respective adjacent switching transistor
40. Referring to FIG. 4, an alternative embodiment of the present
invention is shown. Here, column signal line C.sub.2, is only
coupled, via a respective switching transistor 40, to each of the
green pixel electrodes 16 in each adjacent column of pixel
electrodes. The other two column signal control lines C.sub.1 and
C.sub.3 are coupled to two different colors of pixel electrodes in
adjacent columns of pixel electrodes 16. As shown, both signal
control line C.sub.1 and C.sub.3 are coupled via switching
transistors 40 to each of the blue and red pixel electrodes 16 in
adjacent columns. When signal control line C.sub.1 is providing
pixel information to the red pixel electrodes 16 of the adjacent
columns, signal control line C.sub.3 is providing pixel information
to the blue pixel electrodes 16. Thus, as the odd row control lines
26 are scanned, pixel information for the red pixel electrodes is
provided on control line C.sub.1, green pixel information is
provided on signal control line C.sub.2, and blue pixel information
is provided on signal control line C.sub.3. When the even row
control lines 26 are scanned, switching circuit 50 reverses the
connections of the R and B source lines 51 to the corresponding
color signal busses 52 and 56 such that signal column line C.sub.1
provides blue pixel information to the blue pixels 16 and signal
column line C.sub.3 provides pixel information to the red pixel
electrodes 16 in the adjacent columns. This arrangement somewhat
simplifies the switching circuit 50 and control arrangement shown
in FIG. 3. One column control, such as C.sub.2, line is always
dedicated to one color of pixel electrodes 16, wherein the other
two column signal control lines alternately control the red and
blue pixel electrodes 16. Again, whether an odd or even row control
line 26 is being scanned dictates whether switching circuit 50 is
routing the red pixel signals on R to color signal bus 52 or 56,
and whether the blue pixel signals on B are being routed to color
signal bus 56 or 52.
Another alternative embodiment of the present invention is shown in
FIG. 5. Here, each of the two blue pixel electrodes 16 for a
particular triad 22 are electrically connected together via a
conductive bridge (80). Only one switching transistor 40 is
required to provide pixel information from the respective signal
control line 30 to each of the blue pixel electrodes. Thus, only
one switching transistor 40 is required for each of the three
colors of pixel electrodes in a triad 22. In other words, only
three switching transistors 40 are required for each triad 22.
Referring now back to FIG. 3, one of the principal features of the
present invention is that 480 row control lines 26 are used for 720
pixel electrodes 16 in each column, with the bifurcated blue
electrode being considered one electrode. Thus, a standard 480
active line colored video signal can be directly mapped onto a
display panel structure having 720 columns of electrodes 16.
Further, the 720 pixel electrodes 16 in each row, wherein each
triad 22 comprises electrodes of two adjacent columns, are
partitioned such that there are a total of 360 triads of pixels 16
in each row which also corresponds to the number of pixel samples
per line of the video source. Thus, the video source having 480
active colored signal control lines with 360 signal source samples
can be directly mapped onto the display of the present invention.
No auxiliary memory or line storage components are required. The
rotation of the triads 22 by 90.degree. provides for a unique
display without requiring a "ping-pong" memory. High resolution is
maintained, the control electronics remain simple and manageable,
and the current manufacturing techniques can be implemented.
It is noted that the present matrix architecture could be employed
in other matrix technologies as well including, but not limited to,
EL displays, plasma displays, and field emission displays. Hence,
limitation to an LCD display is not to be inferred.
This invention has been described herein in considerable detail in
order to comply with the Patent Statutes and to provide those
skilled in the art with the information needed to apply the novel
principles and to construct and use such specialized components as
are required. However, it is to be understood that the invention
can be carried out by specifically different equipment and devices,
and that various modifications, both as to the equipment details
and operating procedures, can be accomplished without departing
from the scope of the invention itself.
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